It is known that, after performing certain surgical procedures on a patient, it can be desirable to place a membrane barrier on the site of the operation. Such membrane barriers exclude cell types such as epithelial elements, thereby promoting "productive" cell lines with the aim of encouraging qualitative and quantitative regeneration of functional tissue.
There are many clinical situations wherein a secondary means of fixing and retaining the appropriate membrane barrier to the underlying tissue structure is essential if the tissue regenerative process is to be encouraged.
It has long been recognised that secondary surgical interventions undertaken for the sole purpose of removing non-absorbable "scaffolding" structures (placed at the time of primary surgery) are undesirable. Apart from the additional discomfort and inconvenience to the patient, the secondary intervention can prejudice the quality and speed of the delicate biological regenerative process initiated soon after the placement of the membrane barrier.
The current systems available for providing membrane support are constructed from highly engineered medical grade titanium alloys. Apart from the disadvantages of requiring secondary surgery, as mentioned above, such titanium alloy systems are extremely expensive and require expensive manipulating instruments, such as drivers, graspers and surgical mallets. In addition, there is considerable difficulty with handling and manipulating such systems. Furthermore, the size constraints of existing designs can render it difficult to obtain adequate purchase in spongy cancellous bone.
It has therefore been considered desirable to provide a tissue tacking system made from a resorbable material, thereby precluding the need for secondary surgery, and to provide a system which overcomes the other disadvantages of conventional systems mentioned above.
Bone pins have therefore been made from synthetic resorbable polymers so as to overcome the need for secondary surgery. However, such bone pins have relied upon screw threading for retention, and this presents a major inherent problem in that they are unable to resist the high torque forces produced when attempting to fix them into dense bone.
It would therefore be desirable to provide a resorbable surgical pin which overcomes this disadvantage.
Pins made from synthetic resorbable polymers are known. These are of hollow construction to allow the pins to become infiltrated by, incorporated by, and ultimately resorbed by host tissue. However, this construction necessarily complicates the manufacturing process and is not feasible for pins having small dimensions. Furthermore, such a hollow construction is not necessary for facilitating the processes of guided tissue and/or bone regeneration.